The seventh and final season of the original Mission: Impossible originally aired Saturdays at 10:00-11:00 pm on CBS from September 16 to December 9, 1972 and Fridays at 8:00-9:00 pm from December 22, 1972 to March 30, 1973.
The fifth season of the original Mission: Impossible originally aired Saturdays at 7:30-8:30 pm from September 19, 1970 to March 6, 1971. "The Merchant" originally aired Wednesday, March 17, 1971 at 7:30-8:30 pm.
The first season of the original Mission: Impossible originally aired Saturdays at 9:00-10:00 pm on CBS from September 17, 1966 to January 7, 1967 and at 8:30-9:30 pm from January 14 to April 22, 1967.